Variable-speed mechanism.



'S. B. GRAY, DEGD.

B. s. GRAY, ExnoUToB. VARIABLE SPEED MEGBLANISM. APPLIoATIoN FILED MAY 5. 1906.

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- s. B. GRAY, DBGD.

.1a. s. GRAY, nxnoUToR. l VARIABLE SPEED MEGHANISM.

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UNITED STATES. PA'rENr oEEroE.

{STEPHEN B. GRAY, or JAoKsoNvLLE, I'LLlrNors; BARTLETT s. GRAY EXEoUToR or sAID STEPHEN B. GRAY, DEoEAsEn.

No. easjvss.

specification of Letters Patent.

Patented June 1, 1909.

Appnoatin mea May' 5, `'1906. serial No. 315,281.

To all whom 'it may concern:

Be it known that 1, STEPHEN B. GRAY, ai 'resident of Jacksonville, in the county of` Morgan and State of Illinois, have invented. certain new and useful Improvements in Variable-Speed Mechanism, of which the following is a full, clear, and exact description.

The invention relates to variable speedmechanism and designs to rovide an improved construction of a varlable ulley and improved mechanism for relative y and simultaneously adjusting a pair of pulleys.

The invention consists in the several novel features hereinafter set forth and more particularly defined by claims at the conclusion hereof.

In the drawings: Figure 1 is a plan. view of a variable drive-mechanism embodying the preferred form of the invention. Fig. 2 is a central longitudinal section taken on line 2 2 of Fig. 1. Fig. 2tL is a detail of one of the shifters in position to render one of the pulleys inoperative Fig. 3 is a transverse section on ine 3 3 of Fig. 1. Fig. 4 is a transverse section on an enlarged scale taken on the axial line of one of the portions of the driving mechanism. Fig. 5 is a section on line 5 5 of Fig. 4. Fig. 6 is a similar section illustrating a modified form of connection for the rim section.

The improved mechanism usually comprises a pair of adjustable pulleys respectively mounted on shafts from one of which motion is to be im arted to the other.; These pulleys are of li e construction. They improved pulley, Fig` 4, comprises a body formed of a palr of sides or members and 11, both of which are slidably mountedjon a shaft 12 and connected thereto by a key 13 j so as to revolve to ether with said shaft. Each side of the pul ey comprises a hub 14 and an annulus 15 integrally connected by spokes 14. provided with a series of oppositely inclined guide-bars 16, arranged approximately at an angle of 45o with respect to the wheel-axis. These bars are polygonal in cross-section and secured in each of the sides of the body against lateral and radial movement by ca s 17 and 18 whereby the bars are respective y secured to the hub and annulus of one of the sides of the body. A series of rim-bars or sections 19 extend between the wheel-members and form the adjustable rim of the pulley. Each end of the rim-sections 19 is slid- Each of the sides 10 and 11 is:

ably connected by a box or bearing 20 to the guide-bars 16 of the wheel-members respectively. A cap 21 secures each box 20 to the guide-bar 16 so the rim-section will be moved inward by the guides when the bodysections are spread. A packing 22 is held in each of the boxes to prevent the rim-sections from rattling if the boX should become worn or loose.

One important object of the invention is to provide a pulley comprising longitudinally movable sides or members which are relatively movable and which are connected to the rim-sections so they will be moved positively inwardly or outwardly when adjustment of the body-members occurs. Manifestly by slidably connecting the rim-sections to the angular guides which are on and move with the sides of the body and whereby they are sustained, the rim-sections will be moved positively in either direction radially, and a simple and advantageous construction is provided. The body-sides are held in desired position b a collar 24 arranged adjacentthe outer sideof the hub of each side or member of the body, a ball-bearing 25 being inter osed between the hub and col ar. This ballearing receives the thrust of the bodymembers which, when the belt is strained tends to force the sides of the body apart. The body-sides are caused to move outwardly with collars 24 by screws 26 which are adapted to engage a flange 27 on the hub. Thus it will be seen that when the collars are shifted by the mechanism hereinafter described, the diameter of the rim can be readily varied and that the rim-sections 19 are connected to the sides of the pulley in such manner that they will positively res nd in either radial direction to the relative longitudinal movement of the sides whereby they are su ported.

Eac of the collars 24 whereby the sides are held against lon itudinal movement on the shaft 12 is provided with a pair of arms 28 arranged at the sides of the shaft and lprovided with projecting trunnions 29 on w ich a collar 30 1s journaled. Arms or levers 31 secured to turn with a shaft have their distal ends projected through eyes 33 in the collars 30 so that oscillation of shafts 32 will move the collars 24 longitudinally on shaft 12 and cause corresponding shift of the sides of the body. It W1ll be understood that collars 24 are non-rotatable, the ball-bearing 25 forming an anti-friction bearing between the rotating hub and the stationary collar.

Usually in variable speed-mechanism two adjustable pulleys are operated together, and the size of one pulley is increased and the other correspondingly diminished, so the mechanism lcan be continuously operated without change of structure or variation of the length of the belt. ln the drawings there is shown such a mechanism embodying adjustable pulleys A and B of the improved construction hereinbefere described, and a belt C operatively connecting the pulleys so one will be driven by the other. Each pulley is mounted upon a shaft 12 which is mounted in hangers 35 secured to a frame 36 which may be of any suitable ecnstruction. The frame comprises lower supporting-bars 37 on which the adjustingshafts 32 for each of the pulleys are journaled, each of said shafts being mounted iu bearings 38 secured to frame-bars 37. An adjusting-shaft 32 is provided for each side of each pulley. Each shaft 32 extends longitudinally of the frame at one side of the wheel-side operated thereby and near the center thereof has a horizontally extending arm 40 rigidly secured thereto. The mechanism for adjusting shafts 32 and holding them in position to secure the sides of both pulleys 1n position to render the driving mechanism operative, comprises a shifter 41 slidably mounted in bearings 42 secured to the underside of cross-bars 43 of the frame. A shifter 41 is provided for adjusting the shafts 32 for the corresponding sides of each of the pulleys and each shifter is provided with a cam 41rl for adjusting one of said shafts and a reversely formed cam 41 for adjusting the other of said shafts. A. roller 45 mounted on the end of each of the arms 40 engages one of the cams on the shifter and is shifted vertically thereby. This slidable cam is formed and arranged so that when shifted in one direction it will cause the arms 40 of the adjusting shafts at one side to be shifted in opposite directions respectively, that is to say, when the cam is shifted in either direction, one of the arms 40 will be shifted downwardly and the other will be free to move upwardly.

The cam edges are properly shaped to secure the sides of the pulley in position to position the rim-sections, the belt will be taut in response to the adjusting mechanism, and so the belt will be maintained in operative relation with respect to the rims of the pulleys during various adjustments. ln order to maintain this relation differential shift of the pulleys is necessary. When the pulleys are adjusted to be driven at the same speed the straight reaches of the belt are shorter than when there is material difference between the diameters of the rims. Therefore it is necessary to provide mechanism which effects diill`erential adjustment of the pulleys so that when they are substantially of the same diameter, the pulleys will be adjusted to keep the belt taut despite the shortness of the straight reach of the belt and so that when the pulleys are of substantially different dialneters the rim-sections will be adjusted to maintain driving relation of the belt and pulley. For this purpose the earn surfaces -41a and 41 are substantially V shaped instead of straight and adjust the sides of the pulleys to compensate for this xf'ariation. ln the cam shown the eenter-prutimis 4b" and 42 of the cams are shaped so that the aggregate diameter of the two pulleys will be slightly greater when the pulleys are adjusted for like speed and will cause gradual decrease of the aggregate dianwters as the pulleys are adjusted for greater or less speed. llesultantly the differences in the. a ;;jregate diameters of the pulleys neeessary at dill'erent times to keep the belt taut and in driving relation on the pulleys is maintained by the compensating adjustment caused by the cams.

The mechanism for shifting both shifters 41 conjointly comprises a cross-shaft 47 mounted in straps 4S secured to the erossbars 43 of the frame and a pinion 4E) l'or eugaging each rack 50 on the shifters. A gear 5l and worm-wluiel 52 serve to adjust the shaft as desired. lt will be understood that the shaft, of worm-wheel 52 nur v he inauually operated when adjustment is desired by a hand-wheel 53. lf desired springs 55 can be employed for shiftingl wheel sides outwardly under the Control of the shiftercams and independently of the belt.

A recess 44 in the shifter serves to throwor'l the belt when desired, e. (,f., when the shifters are operated into position seen in Fig. 2, the rim-sections of the driven pulley will beheld out of engagement with the belt and the belt will be loose and inoperative. The edges of the shifter 41 around recess 44 are inclined to gradually loosen the belt. Such formation of the cam causes the rimsections to be gradually expanded and operate in the same manner as a friction-clutch in lieu of causing sudden shift of the rim-seetions by which the belt will be torn or strained. rlhis feature is of advantage bccause the same mechanism which adjusts the belt can be used as a throw-olf mechanism. Vllhen adjustment of the variable drive-mechanism is desired, it is only necessary to adjust shaft 47 which operates both of the Shifters 41. The cams on these shifters will control the operation of the adjusting j shafts 32 for the pulley-sides of both pulleys by means of arms 40, shafts 32, arms 31 and collars 24. ln Fig. G is illustrated a modilied form of bearing box for connecting` the rimsections and the guides 16 of the adjustable pulley sides. Said bearing comprises rollers 22 which are journaled in the box and roll along the guides when the pulley-sides are shifted.

The invention provides a variable pulley which is simple in construction and in which the adjustable rim-sections are connected to the body of the wheel of the pulley and adjusted thereby in either direction. The improved adjusting-mechanism involves slidable cams which have been found to be of special advantage in effecting the differential adjustment of the pulleys necessary to keep the belt taut. Furthermore the adjusting mechanism can be used as a throw-off mechanism and friction-clutch for the belt.

The invention is not to be understood as restricted to the details of construction set forth but may be varied without departing from the spirit and scope of the invention.

Having thus described the invention, what I claim as new and desire to secure by Letters Patent, is:

1. In a pulley, the combination of a shaft, a body comprising a pair of sides each slidable axially on the shaft, a series of inclined rods on each of the sides and secured at their inner and outer ends to the sides respectively, rim-sections slidably connected to the rods so as to be moved inwardly or outwardly thereby, non-rotatable collars for shifting the sides respectively, and means for simultaneously shifting said collars inwardly or outwardly to adjust the wheel sides.

2. In variable drive-mechanism, the combination of a pair of pulleys comprising radially adjustable rim-sections, a belt connecting the pulleys, and slidable cams whereby the rim-sections of the wheels may be differentially adjusted to keep the belt taut.

3. In variable drive-mechanism, the combination of a pair of pulleys each comprising a pair of axially movable members, and radially adjustable rim-sections, and mechanism for shifting the sections comprising slidable cams whereby both of said members will be shifted. 1

4. In variable drive-mechanism, the combination of a pair of pulleys comprising a pair of axially movable members, and radially adjustable rim-sections, and mechanism for shifting the sections comprising slidable cams whereby both of said members will be shifted differentially.

5. In variable drive-mechanism, the combination of a pair of pulleys each comprising adjustable rim-sections, a belt connecting the pulleys, and mechanism for adjusting the sections comprising a longitudinally movable shifter provided with cam-surfaces whereby the rim-section of both pulleys will be differentially adjusted.

6. In variable drive-mechanism, the combination of a pair of pulleys comprising adjustable rim-sections, a belt connecting the pulleys, and mechanism for adjusting the sections comprising a cam formed to operate as a throw-off.

7. In variable drive-mechanism, the combination of a pair of pulleys comprising adjustable rim-sections, a belt connecting the pulleys, a cam, and connections whereby the sections will be adjusted by said cam, said cam having a surface whereby the sections may be gradually shifted to operatively connect and disconnect the belt and pulleys.

8. In variable drive-mechanism, the combination of a pair of pulleys comprising adjustable rim-sections, a belt connecting the pulleys, a cam, and connections whereby the sections will be adjusted by said cam, said cam having a surface whereby the sections may be shifted to render the belt inoperative.

STEPHEN B. GRAY.

Witnesses:

R. M. HOLKENHULL, J. ALLERTON PALMER. 

